The amount of student learning and personal development that occurs in a classroom is directly proportional to the quality and quantity of student involvement in the educational program (Cooper & Prescott, 1989). Descriptive research indicates that teachers still typically dominate classroom conversation, although many more teachers have started to incorporate more student-centered educational approaches into their instruction. A large portion of teacher talk consists of lectures and directives. Such an educational environment results in learners' assuming passive roles and relying mainly on auditory skills, a limited dimension of the intellect. Problem-based learning (PBL) modules diminish teacher talk. By teaming students with one another, students have frequent opportunities to talk as they construct knowledge themselves in the course of solving a problem. Thus, students may use more of their intellect in PBL than they use during traditional lecture instruction.

Team Size

Depending on the nature of the task associated with one of the Global Climate Change PBL modules, cooperative teams may have two, three, or four students. Pairing is ideal because it maximizes student participation. Pairs start to work easily and tend to maintain involvement. Pairs tend to make less noise than larger teams.

However, you will find some Global Climate Change PBL modules require more input than a pair is likely to be able to generate, depending on how much classroom time you are allowing for the module. When a task calls for much creativity or many different perspectives, use teams of three or four. Teams larger than four may lead to passive participation (Harmin, 1994).

Helping Teams Function Smoothly

Harmin (1994) feels that letting teams self-select has many advantages. Teams form quickly and students learn how to respond when others reach out to them. Many teachers prefer this method of forming teams even though it can present some problems. On the other hand, you may prefer to assign students to teams, You know your students and their personalities and can head off problems by forming teams with members who may not already be antagonistic toward each other. Even this approach may not prevent problems from developing. Below are some common problems, followed by suggestions from Harmin (1994) and others.

Problems When Teams Self-select

Students keep choosing the same people for their groups, and cliques begin to form. Harmin (1994) advises you to urge the students to get to know and work with more than just a few students. You can strongly suggest that students risk asking someone they haven't worked with before to be their partner or ask if they would prefer to have you do it. Occasionally, if all else fails, you can direct some students to not sit with each other again for the next two weeks.

Sometimes nobody wants to sit with one of the students in the class, and you have to intervene several times to get the outsider into a team. Harmin (1994) suggests speaking privately to a few of the students with whom you have a good relationship. You should ask them if they've noticed that all students aren't readily accepted by others when teams are formed. Suggest that they go out of their way to look for students who are being left out. In this way they would be modeling for the rest of the class the supportive team spirit that is so vital to teamwork. It is not necessary to mention the left-out student by name (Harmin, 1994).

Slower students always sit together and cannot do some of the academic work. Harmin (1994) advises that you suggest that these students pick different partners in the future and remind the entire class to ask other teams for help whenever they reach an impasse.

Problems That Can Develop in Any Team

A few students persist in gossiping and doing little work in their teams. Harmin (1994, p. 98) says, "Don't 'complain or scold'; those tactics will likely be counterproductive." He suggests you resist intervening the first time you notice the behavior. If the behavior continues, simply walk over to the students and calmly point out that they are responsible for their learning and that they need to get down to work. If this does not work, again skip any warning such as "I'll change your teams if you do not settle down to work," and simply announce that because you want everyone to learn in class, you want them to choose other students to work with during the next two weeks.

One person takes over while others sit back and say little. Maintaining individual accountability will help prevent this from occurring. An individual report, demonstration, or final product will hold each team member accountable for his or her participation. In addition, you may want to randomly call on individuals to give an update or summarize the main points of a reading or discussion.

Group expectations become self-fulfilling. That is, if the group expects a low-status student to perform below the level of the group, he or she will. The best way to ensure that all students participate competently is to design individual tasks that require each student to use his or her particular strengths. When students are prepared with mixed expectations for competence, low expectations of one group member tend to disappear (Cohen, 1990).